A differential input receiver may receive differential inputs at input/output pads of an integrated circuit. Input signals may have a range of common mode voltages (VCMs). In many cases, it may be necessary to shift the differential input signals to generate a signal having a different common mode voltage within the integrated circuit receiving the differential input signal.
However, shifting a common mode voltage may have a number of drawbacks. For example, when implementing an AC coupled receiver input, blocking capacitors may allow for independent receiver and transmitter common mode levels, but such solutions may have a high-pass characteristic with a given cut-off frequency, where signal loss below this cutoff frequency leads to base line wander. DC coupled solutions may be hampered by common mode level restrictions, offset complications or undesirable design trade-offs for component values.
Accordingly, methods and circuits for implementing a differential input receiver that enable the shifting of the signal are beneficial.